Design and experimental evaluation of feedforward controller integrating filtered-x LMS algorithm with applications to electro-hydraulic force control systems
Design and experimental evaluation of feedforward controller integrating filtered-x LMS algorithm with applications to electro-hydraulic force control systems
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DOI：
10.1177/0954406215584810
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发表时间：
2016-07
期刊：
影响因子：
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通讯作者：
Yu Tang;Zhencai Zhu;G. Shen
中科院分区：
文献类型：
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作者：
Yu Tang;Zhencai Zhu;G. Shen
电液力控制（EHFC）系统的控制目的是在实验室中实时复制施加在结构上的力，以模拟无法自然产生的载荷。与电液位置控制系统相比，EHFC系统的跟踪性能总是有限的。为了提高EHFC系统的力复制精度，本文提出了一种集成滤波-x LMS自适应算法的前馈逆控制器。所提出的控制器包括一个前馈逆控制器和一个自适应控制器。首先利用比例积分控制器将所设计的参数逆传递函数直接级联到EHFC系统中，建立了作为内环的前馈逆控制器，并通过系统辨识和零量级误差跟踪技术获得了逆传递函数。然后，将采用滤波-x LMS算法的自适应控制器作为外环与前馈控制器相结合，以处理模型逆设计过程中出现的误差。因此，所提出的控制器是一种易于实现的策略，可以有效地提高相位延迟误差和幅度失配误差下的力复制性能。最后，利用xPC靶技术在实际EHFC试验台上进行了一系列实验，实验结果表明，与比例积分控制器和前馈控制器相比，所提出的控制器具有相对更好的跟踪精度。值得注意的是，所提出的控制器也可以扩展到其他需要高精度跟踪性能的伺服控制系统。
The control purpose of an electro-hydraulic force control (EHFC) system is to real time replicate the force exerted on a structure in laboratory so as to simulate loads that cannot otherwise be generated naturally. In contrast to electro-hydraulic position control system, the tracking performance of EHFC system is always limited. To enhance the force replication accuracy of EHFC systems, a feedforward inverse controller integrating filtered-x LMS adaptive algorithm is presented in this paper. The proposed controller comprises a feedforward inverse controller and an adaptive controller. The feedforward inverse controller working as an inner loop is firstly established by directly cascading the designed parametric inverse transfer function to the EHFC system with proportional integral controller and the inverse transfer function is obtained with the implementation of system identification and zero magnitude error tracking technology. Then, the adaptive controller employing the filtered-x LMS algorithm acting as an outer loop is further combined with the feedforward controller to deal with the error occurred in the inverse model design procedure. Therefore, the proposed controller is an easy-to-implement strategy and can effectively enhance the force replication performance for both phase delay errors and amplitude mismatch errors. Finally, a series of experiments are carried out on a real EHFC test rig by means of xPC target technology, and the experimental results indicate that the proposed controller has a relatively better tracking accuracy compared with the proportional integral controller and the feedforward controller. It is also worth noting that the proposed controller can also be extended to other servo control systems where high accuracy tracking performance is required.